Boundary tower



FIG. 1 is a top perspective view of a boundary tower;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a right side elevation view thereof;

FIG. 5 is a left side elevation view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is a transverse section view thereof, taken along line 8-8 of FIG. 2; and,

FIG. 9 is a front-to-rear vertical section view thereof, taken along line 9-9 of FIG. 2.

The broken lines illustrate boundaries that form no part of the claimed design. 

CLAIM We claim the ornamental design for a boundary tower, as shown and described. 